In “A Biographical
Sketch of an Infant”, Charles Darwin details his infant son’s pattern of growth
and development in an effort to attempt to determine which actions, on the part
of the infant, were learned and which actions were instinct. Darwin
kept a well-written account of his infant son as he grew. It wasn’t until Darwin read a book that gave an account of an
infant’s mental development that he felt compelled to look back at his own
notes as a source of comparison.

Darwin
determined that a number of reflexes that he witnessed his infant perform in
the first week of his life were indeed reflexes. Darwin
stated, “During the first seven days various reflex actions, namely sneezing,
hiccupping, yawning, stretching, and of course sucking and screaming, were well
performed by my infant.” In a slightly
comical way, Darwin
then goes on to talk about the great lengths he went to in order to startle his
child